1. Field of the Invention
The invention relates to a temper mill installation having an uncoiler for coils of steel strip, a rolling mill for the steel strip, a shearing machine for cutting the steel strip and a coiler for the steel strip rolled by the mill. The invention also relates to a shearing machine for use in the temper mill installation. A temper mill may be a skin-pass mill. A use of such a mill is hardening, especially cold-hardening.
2. Description of the Prior Art
Temper mill installations of the type described above are known in rolling mill practice. The shearing machine used is usually equipped with guillotine shears. Because of the size of the known shearing machine it is customary to position it between the rolling mill and the coiler. However, this has the disadvantage, explained below, that for each coil worked in the temper mill installation a number of meters of steel strip cannot be treated, and are unnecessarily wasted.
The innermost turns of a coil, which is placed on the uncoiler, are generally damaged in such a way that to pass those turns through the rolling mill could result in damage to the mill rolls. Immediately before the damaged turns reach the rolling mill, the rolling process is therefore stopped. Then the quillotine shears positioned at the discharge end of the rolling mill are operated, after which coiling can be completed. The part of the strip which extends from the damaged turns on the entry side of the rolling mill to the position of the shearing machine is of good quality. Nevertheless, this part of the strip is separated from the coil of steel strip which has meanwhile been wound on the coiler, and must be treated as waste.
A further disadvantage of the known temper mill installation is that the strip remaining behind in the rolling mill still has to be removed. This is generally solved by causing the uncoiler after the shearing machine has operated, to coil up the uncoiled strip by reversing the direction of rotation of the uncoiler. This however reduces the production capacity of the temper mill installation and imposes extra requirements on the control of the uncoiler.
It is known from GB-A-868,867 to remove, by shearing, service tails from coiled metal strip, particularly strip which has been cold-rolled in a reversing mill, while uncoiling the strip for further treatment. This further treatment is in particular softening and descaling.